The embodiments herein relate generally to an apparatus and method for analyzing a human's breath.
The human breath is complex and is estimated to have as many as 200 different gas components in a typical sample. Some of these gases are present in small quantities such as 1-100 parts per billion (ppb), which presents a need for accurate methods and devices to properly detect these components.
Several optical and chemo-resistive analyses have been used to determine the ratio of gases present in a sample. Optical analyses are conducted through the use of sensors known as opto-sensors. Gases in a sample are exposed to a light generated by a source. The interaction of the gases with the light causes the intensity and/or wavelength of light to change. By analyzing the change in wavelength of the light, the ratio of gases present in a sample can be estimated.
Chemo-resistive analyses are conducted through the use of sensors known as chemo-sensors or electro chemo-resistive material. During these analyses, gases in a sample interact with the sensors, which causes the resistance properties of the sensors to change. The sensing material of the chemo-sensors are generally heated to a high temperature within the range of 50-700 degrees Celsius. This heating process increases the selectivity and sensitivity of the chemo-sensors to the present gases. For example, a chemo-sensor's resistance can change dramatically in the presence of oxygen when heated to 400 degrees Celsius, but not very much at other temperatures. The same chemo-sensor's resistance might change dramatically in the presence of acetone when heated to 600 degrees Celsius. By measuring the resistances of one or more chemo-sensors at various temperatures, the ratio of gases present in a sample can be estimated.
Although there are numerous studies on the development of optical and chemo-resistive techniques and devices, the development of portable devices with the capability of detecting trace amounts of gases in a sample remain a challenge.
As such, there is a need in the industry for a gas collection apparatus and method for determining the ratio of gases in a sample with enhanced accuracy. Specifically, there is a need for a gas collection apparatus and method that combines both optical and chemo-resistive analyses to determine the ratio of gases present in a human's breath sample.